1. Field of the Invention
The invention relates to a system for personalized information distribution (PID) from an information source server to several user terminals via an information distribution network.
The proposed PID service aims to provide tailor-made information distribution to receivers using different devices, access technologies and access speeds. Examples of PID services are live television in a user's own format/speed and language, real-time stock exchange information of your favorite stocks on various devices, or distribution of a video stream to many end-users with different access technologies, access speeds, and various requirements regarding QoS.
2. Description of the Prior Art
In current IP networks, it is difficult to distribute information, e.g., a video stream, to many end-users with different access technologies and access speeds. Some possible solutions are:                sending multiple videostreams with different quality classes (e.g., 33 kbps on PSTN, 64 kbps on TSDN, 500 kbps on ADSL, etc.);        sending the videostream with the lowest quality and decreasing the service f or the end-users connected with higher speeds;        selective discard of information elements, e.g., low priority videoframes in hierarchically encoded schemes. These solutions can be implemented using traditional point-to-point IP, or using IP-multicasting. The former is resource-intensive, but mechanisms for quality differentiation exist; the latter is resource efficient, but the creation and management of large multicast is complex. Moreover, until now IP-multicast only supports best-effort.        